Building in a new sustainable way with SSAB Weathering steel

The construction industry and use of buildings accounts for 39 percent of global CO2 emissions. And in Europe, construction is the top steel-consuming industry. The potential to reduce CO2 is huge. So, how can we contribute by making infrastructure more sustainable? Or the steel it uses more sustainable?

SSAB Weathering steel comes ready to use without galvanizing or painting. This already marks a significant step towards more sustainable infrastructure at a reasonable cost. With its high strength, it enables a lower steel weight and related embodied carbon. But the story doesn’t end here. In the future, you’ll be able to get all this in an entirely fossil-free steel. The shift to fossil-free steel solutions for infrastructure is underway, and the time to start designing sustainably is now.

Even if you do decide to paint it, you can double the intervals for maintenance painting compared with conventional basic carbon steel.

Ready to use, no galvanizing or painting needed

The benefits of skipping the coating processes and associated negative environmental impacts are significant. For example, the European average for hot-dip galvanizing a ton of steel accounts for more than 120 kg of CO2 emissions. And about 160 kg of CO2 emissions are embodied when painting that same amount. On top of this, these processes involve significant costs and longer lead times.

With SSAB Weathering steels, you can avoid such embodied carbon emission and cost-intensive coatings over the product’s lifespan. Instead, weathering steel´s patina develops naturally over alternating wet-dry cycles in atmospheric conditions, which slows down corrosion and provides a service life comparable to coated carbon steel when applied properly. Fully naturally, without any active industrial process. As for any future maintenance, your structure won’t require coating removal or disposal of contaminated blast debris.

Even if you do decide to paint it, you can double the intervals for maintenance painting compared with conventional carbon steels. This means significant savings for your maintenance schedule and budget.

Test results in atmospheric conditions demonstrate superior service life against corrosion

The Technical Research Center of Finland, VTT, conducted a corrosion test for four different bridges made out of SSAB Weathering steel. This test provided performance data from real atmospheric conditions in Finland over a 32-year period. The results confirm that weathering steel´s general corrosion rates under C2 and C3 atmospheric conditions make them a good choice with minimal corrosion allowances. The tests also demonstrated that just within the first 5 years after commissioning, loss due to corrosion dropped drastically as the patina stabilized.

Test results from real atmospheric conditions in Finland

Bridges in Finland: Cumulative corrosion loss of 32 years (1982–2014), material COR-TEN B

Bridges in Finland: Cumulative corrosion loss of 32 years (1982–2014), material COR-TEN B

Source: VTT-CR-05247-14, Säänkestävien teräslevyjen korroosiotutkimus v. 2014, Leena Carpen, VTT Technical Research Center of Finland.

Lower embodied carbon emissions with high-strength steel

High-strength steel enables you to use less steel in structural designs. This brings a corresponding saving potential in embodied carbon emissions – potentially up to 40-50% – so that investments in structural redesign needed for existing structures can really pay off.

Theoretical reduction potential of embodied carbon by using SSAB Weathering high-strength steels

Development of corrosion loss (µm/a) over the lifetime

Source: VTT-CR-05247-14, Säänkestävien teräslevyjen korroosiotutkimus v. 2014, Leena Carpen, VTT Technical Research Center of Finland.

SSAB has developed a wide range of weathering steel in yield strength levels up to 960 MPa, which enable lower steel weight of the structures even with typical corrosion allowances of weathering steel. This means that corrosion allowances needed for weathering steel don’t necessarily increase the weight, and when combined with high-strength grades the steel weight and related embodied carbon can be lowered, too. This opens up new application possibilities especially in the thin range of 3-8 mm.

Recently, some high-strength weathering grades have been also standardized in Europe under harmonized products standards EN 10025-5:2019 and EN 10219-3:2020 for flat and tube products, and the steel structures made out of these grades can be also CE-marked by the customer. Consequently, interest on the European market for this unique combination of weathering properties connected to high strength has been steadily rising.


Use better steel – go emissions-free with SSAB

SSAB is already one of the world’s most CO2-efficient steel companies. But thanks to our new approach to steel production, we are forging a path to introducing the market’s first fossil-free steel by 2026 and making our entire operations fossil-free 2045. SSAB Weathering steel will be part of this transformative offering.

SSAB’s Environmental Product Declarations (EPDs) comply with international standards, and they provide objective data highlighting the low carbon footprint of our products. SSAB Weathering steels are covered by EPDs as per ISO 14025:2006 and EN 15804:2012. And in the future, fossil-free weathering steel will be documented in an independently reviewed EPD and will conform to strict European and international standards. This assurance will cover all aspects of the steel production process, delivering a decarbonized value chain to our customers.


10 good reasons to use SSAB Weathering steel

Making the right material choices can have a huge impact on the sustainability profile of a steel structure. Here are 10 good reasons to use SSAB Weathering, with regard to product performance, environment and costs:

  • Comparable service life to coated carbon steel, 40-100+ years in C3 when applied properly
  • Ready to use - no need for galvanizing or painting means lower costs already in the construction phase
  • When a painted surface for aesthetical reasons is required, doubling the interval for maintenance painting brings lower maintenance costs
  • High-strength weathering products available in yield strengths 420, 460, 500, 550, 700 and even 960 MPa, enabling lower embodied carbon of lighter steel structures
  • We already use the cleanest steelmaking practices and are leading the way towards fossil-free steel in industry
  • No zinc run-off to the environment
  • No coating damage in installation or transport
  • No release of harmful chemicals related to painting and paint disposal
  • No indirect costs of traffic delays or the closure of bridges and infrastructure due to maintenance
  • Natural color and appearance